The present invention relates to graphic drum plotters and, more particularly, to a guide apparatus for guiding strip paper from a supply roller across a vacuum column and into the space between the drum and beam/writing head during loading of the paper.
A typical graphics drum plotter is shown in simplified form in side cross-section and generally indicated as 10 in FIG. 1. The plotter 10 includes a supply roller 12 having strip paper 14 thereon, a vacuum chamber 16 having a rear wall 18 and a front wall 20, a drum 22, a beam 24 having a writing head 26 carrying a pen 28 mounted thereon, and a cover 30 hinged at 32 for covering the top of the working portion of the plotter 10. During loading, the paper 14 must first be positioned as shown in FIG. 2 wherein it spans across the top of the vacuum chamber 16 and into the space between the drum 22 and the beam 24/writing head 26. As shown in FIG. 3, the paper 14 is then drawn down into the vacuum chamber 16 to form a loop 34 by vacuum created thereunder in the area generally indicated as 36. The problem involved is that of getting the paper 14 from the position of FIG. 1 to that of FIG. 2. There is not enough space for an operator to reach between the drum 22 and the bottom of the beam 24 at the area of the arrow of FIG. 1 so as to grasp the paper 14 adjacent the supply roller 12 and pull it through. The supply roller 12 can be rotated, but that only causes the paper 14 to descend down into the vacuum chamber 16. Wherefore, it is the object of the present invention to provide a guide apparatus for simply and easily guiding the paper 14 from its position of FIG. 1 adjacent the supply roller 12 to a position between the drum 22 and beam 24/writing head 26 as shown in FIG. 2 wherein it can be grasped during loading procedures.